BACKGROUND: The SARS-CoV-2 pandemic significantly impacted professional and private lives, which influenced social and health-related behavior. Schools in particular were greatly affected as restrictions made teaching more challenging, leading to new stresses and additional workloads. Prior to the pandemic, teachers were already facing many physical and psychological stressors that were exacerbated by the pandemic. This may have resulted in a deterioration in the teachers' health behaviors. Therefore, the aim of this study was to examine the prevalence of cigarette smoking and physical activity among German teachers during the SARS-CoV-2 pandemic, to assess possible changes considering cigarette smoking and physical activity habits during the pandemic compared to the pre-pandemic period, and to identify predictors of teachers' cigarette smoking and physical inactivity during the pandemic. METHODS: In March 2021, a nationwide online survey was conducted among teachers in Germany. A total of 31,089 participants entered the analysis. Data on cigarette smoking and physical activity as well as sociodemographic, workplace-related, psychological, SARS-CoV-2-related, and health-related items were collected using established instruments and, if necessary, self-developed items. Two binary logistic regressions with stepwise inclusion of six different variable groups were performed to predict cigarette smoking and physical inactivity. RESULTS: Among all surveyed teachers, 13.9% reported smoking cigarettes, and 76.6% did not meet the physical activity recommendations. The regression analyses revealed 16 significant predictors of cigarette smoking and six significant predictors of physical inactivity. CONCLUSIONS: The predictors revealed in the present study can help target interventions for teachers who are at higher risk for unhealthy behaviors during the SARS-CoV-2 pandemic and potential future pandemics. In particular, the alarming finding that more than three-quarters of teachers were physically inactive during the pandemic should place special emphasis on improving physical activity.